cloak and dagger.

"I have grown to love secrecy. It seems to be the one thing that can make modern life mysterious or marvelous to us. The commonest thing is delightful if one only hides it. When I leave town now I never tell my people where I am going. If I did, I would lose all my pleasure. It is a silly habit, I dare say, but somehow it seems to bring a great deal of romance into one's life."
-Oscar Wilde